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1 | ## | |
2 | ## This file is part of the sigrok project. | |
3 | ## | |
4 | ## Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de> | |
5 | ## | |
6 | ## This program is free software; you can redistribute it and/or modify | |
7 | ## it under the terms of the GNU General Public License as published by | |
8 | ## the Free Software Foundation; either version 2 of the License, or | |
9 | ## (at your option) any later version. | |
10 | ## | |
11 | ## This program is distributed in the hope that it will be useful, | |
12 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ## GNU General Public License for more details. | |
15 | ## | |
16 | ## You should have received a copy of the GNU General Public License | |
17 | ## along with this program; if not, write to the Free Software | |
18 | ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | ## | |
20 | ||
21 | def decode(inbuf): | |
22 | """Counts the low->high and high->low transitions in the specified | |
23 | channel(s) of the signal.""" | |
24 | ||
25 | outbuf = '' | |
26 | ||
27 | # FIXME: Get the data in the correct format in the first place. | |
28 | inbuf = [ord(x) for x in inbuf] | |
29 | ||
30 | # TODO: Don't hardcode the number of channels. | |
31 | channels = 8 | |
32 | ||
33 | oldbit = [0] * channels | |
34 | transitions = [0] * channels | |
35 | rising = [0] * channels | |
36 | falling = [0] * channels | |
37 | ||
38 | # Initial values. | |
39 | oldbyte = inbuf[0] | |
40 | for i in range(channels): | |
41 | oldbit[i] = (oldbyte & (1 << i)) >> i | |
42 | ||
43 | # Loop over all samples. | |
44 | # TODO: Handle LAs with more/less than 8 channels. | |
45 | for s in inbuf: | |
46 | # Optimization: Skip identical bytes (no transitions). | |
47 | if oldbyte == s: | |
48 | continue | |
49 | for i in range(channels): | |
50 | curbit = (s & (1 << i)) >> i | |
51 | # Optimization: Skip identical bits (no transitions). | |
52 | if oldbit[i] == curbit: | |
53 | continue | |
54 | elif (oldbit[i] == 0 and curbit == 1): | |
55 | rising[i] += 1 | |
56 | elif (oldbit[i] == 1 and curbit == 0): | |
57 | falling[i] += 1 | |
58 | oldbit[i] = curbit | |
59 | oldbyte = s | |
60 | ||
61 | # Total number of transitions is the sum of rising and falling edges. | |
62 | for i in range(channels): | |
63 | transitions[i] = rising[i] + falling[i] | |
64 | ||
65 | outbuf += "Rising edges: " | |
66 | for i in range(channels): | |
67 | outbuf += str(rising[i]) + " " | |
68 | outbuf += "\nFalling edges: " | |
69 | for i in range(channels): | |
70 | outbuf += str(falling[i]) + " " | |
71 | outbuf += "\nTransitions: " | |
72 | for i in range(channels): | |
73 | outbuf += str(transitions[i]) + " " | |
74 | outbuf += "\n" | |
75 | ||
76 | return outbuf | |
77 | ||
78 | def register(): | |
79 | return { | |
80 | 'id': 'transitioncounter', | |
81 | 'name': 'Transition counter', | |
82 | 'desc': 'Count rising/falling edges', | |
83 | 'inputformats': ['raw'], | |
84 | 'signalnames': {}, # FIXME | |
85 | 'outputformats': ['transitioncounts'], | |
86 | } | |
87 | ||
88 | # Use psyco (if available) as it results in huge performance improvements. | |
89 | try: | |
90 | import psyco | |
91 | psyco.bind(decode) | |
92 | except ImportError: | |
93 | pass | |
94 |